my usual eating plan for a century or longer ride is:

night before: some kind of pasta with seconds and thirds helpings.

breakfast: oatmeal, coffee, one banana, 1 pt. water.

during the ride: energy gel (Clif Shot, Gu) at the start; then something at every 45 min. - hour depending on the particular challenge of the ride (terrain, pace, weather, etc.) Usually alternate "tech" food and "real" food so, like: gel -> banana -> clif bar -> pb&j -> gel -> banana, etc. I find that working in real food tends to keep my upset from getting too upset.

after the ride: one or two helpings of pasta and some kind of protein.

for shorter rides, it's a lot less regimented. Breakfast stays the same, but I might eat one or two Clif bars or make a couple of stops for ice cream during the ride, and whatever I feel like for lunch aftewards.